President Trump on Thursday railed against the House impeachment hearings, attempting to cast doubt on testimony from a career diplomat posted to Ukraine who said he overheard a phone call between Trump and U.S. Ambassador to the European Union Gordon Sondland.

David Holmes, the political counselor at the U.S. Embassy in Ukraine, testified he heard Trump ask Sondland about the status of investigations Trump sought into former Vice President Joe Biden, Biden’s son Hunter, and his connection to Ukraine energy company Burisma, and a debunked conspiracy theory blaming Ukraine rather than Russia for 2016 U.S. presidential election interference.

The House is trying to determine whether Trump abused the power of his office by withholding military aid to Ukraine and a White House visit in exchange for the investigations.

Trump said though he’s been watching people make phone calls his entire life, “Never have I been watching a person making a call, which was not on speakerphone, and been able to hear or understand a conversation.”

In his opening statement, Holmes said he was sitting directly across from Sondland during a lunch and overheard his call to Trump.

“I could hear the president's voice through the earpiece of the phone. The president's voice was very loud and recognizable, and Ambassador Sondland held the phone away from his ear for a period of time, presumably because of the loud volume,” Holmes said.

He continued: “Ambassador Sondland … went on to state that [Ukraine] President [Volodymyr] Zelensky ‘loves your ass.’ I then heard President Trump ask, ‘So, he's gonna do the investigation?’ Ambassador Sondland replied that ‘he's gonna do it,’ adding that President Zelensky will do ‘anything you ask him to.’"

Holmes said though he did not take notes, “I had a clear recollection these statements were made.”

In prepared remarks Fiona Hill, a former National Security Council expert on Russia and Europe, admonished Republicans for touting a “fictional narrative” that Ukraine was responsible for the 2016 U.S. election interference. She said the story is being propagated by the Russian intelligence services themselves.